The purpose of the proposed research is to examine the metabolic events that affect feeding behavior. Experiments are planned that will examine the effects of dietary fat content on food intake and various metabolic parameters in rats with experimental diabetes mellitus. Other studies, will examine the effects of changes in dietary caloric density on metabolic state and food intake in normal rats in order to determine whether the control of caloric intake is related to the metabolic consequences of the diet. Studies are also planned which will further examine the metabolic effects of hunger-inducing injections of insulin and 2-deoxy-d-glucose. In general, metabolic measurements will be taken that will help characterize the circulating supply of metabolic fuels as well as the hepatic production of energy-yielding substances.